[CentOS] The relationship between udev and MAKEDEV

Nifty Cluster Mitch niftycluster at niftyegg.com
Sat Nov 1 20:20:12 UTC 2008


On Tue, Oct 28, 2008 at 09:54:07AM -0400, Filipe Brandenburger wrote:
> On Tue, Oct 28, 2008 at 00:21, Clint Dilks <clintd at scms.waikato.ac.nz> wrote:
> > 2. Is modifying /etc/makedev.d/01linux-2.6.x likely to cause me issues in
> > future ?
> 
> Possibly, since this file is owned by the MAKEDEV rpm. If there is an
> upgrade in MAKEDEV, it may overwrite this file. Or if it doesn't, but
> there was an addition of a new device there, you would not get the new
> device. I would say it would be safer to create a separate file
> instead of modifying those.

In the future may include a clean install.  Thus the change
needs to be entered in your off line notebook so you can recall
the magic you are building in your box.

Check to see if the RPM builder marked it as a config file.

	rpm -qc MAKEDEV
	rpm -qV MAKEDEV

If it is a config file it will be paired with or as an *rpmnew or *rpmsave
file.
    http://www.redhat.com/docs/books/max-rpm/max-rpm-html/s1-rpm-install-additional-options.html

If it is not a config file you will need to be able to regenerate it 
from your notes.

Adding a local file still requires a notebook entry and also eliminates
the ability to do a simple search for *rpmnew or *rpmsave files.   Sysadmins
need to watch for and as needed clean up these files....

  $ sudo updatedb; locate -i rpm | egrep rpmnew\|rpmsave

.....

The key to udev is that it is "udev - userspace device management".  Today in 
Linux most devices are under udev.    Some devices are critical to system operation
and need to be in place before the user space 'udev' tools can 
picks up  the ball.  The bonds depend on the distro..

    http://git.kernel.org/?p=linux/hotplug/udev.git;a=blob;hb=HEAD;f=README
    http://en.wikipedia.org/wiki/Udev

Another key is that the list of possible devices in a system is large,
very large.  If you look at all the possible devices the list can
burst the limits imposed by major and minor device numbers.  A number
of solutions surfaced to address and manage this overflow -- udev is
one of the solutions that seems to work.


-- 
	T o m  M i t c h e l l 
	Found me a new hat, now what?



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